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Hantarex polo 25-28 No brightness control (SOLVED)

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perjmolsen:

Hi  :cheers:

Again a Hantarex Polo trying-to-fix

My Hantarex Polo has no Brightness control, nothing happens at all when I turn the brightness pot.
Also when the picture changes between black and white, the picture gets nearly all white, and then normal "black" again.

R240 a 180K resistor where OL, changed it to a new 180K but still no brightness control, I checked the resistor afterwards and it is still OK.
D401 is OK

What am I missing?  :notworthy:

princess prin prin:

Check the other parts in the beam current limiting circuit starting from pin 7 of the flyback: R232, C176, D150, C180 and R233, R239, R240.

perjmolsen:

HI  :notworthy:

I have checked them all out of circuit including R238, all tested as in spec  :dizzy:

The only components that where a bit off where the two caps
C176   100nf 250v replaced with a new 104J 250V poly cap
C180   10n 630v replaced wit a new 103J 400V poly cap

Still no change in brightness when I turn the pot on the remote board.

I have made a small video of the brightness issue when the picture changes

perjmolsen:

Well....  :o

Now it is fixed........  :banghead: :banghead:

The only thing that I not did test where the pot it self.... sure that where the issue....!

So funny how things work if a new one is put in....  :laugh2:



Now time to  :cheers:

MKFan4Life:

Congrats on the fix. As I was reading I was like, is he going to check the pot itself? Lol! Glad you fixed it up!

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